It is desirable to know as much as possible about yarn before it is used to manufacture fabric or other products. If the yarn does not have the desired properties, there can be problems in the finished product. Accordingly, it is the desire of the industry to obtain as much information as possible about as much as possible of the yarn being used to make the product. This has created a great demand for automated equipment for analyzing yarn.
In the past there have been developed devices using digital cameras such as CCD arrays to scan moving yarn, and store the scans in a computer, or print them out for analysis. One such device is disclosed in U.S. Pat. No. 4,764,876. That device is adapted for measuring balloons and entanglements in textured yarn by looking for transitions from thin to thick yarn and vice versa. Although such information is useful, the device does not have the versatility to provide more information about the yarn for a variety of reasons, including the fact that the width of the yarn is determined to be the number of pixels that are blocked from receiving light in a given scan of the CCD array. Thus, the device is not sensitive to loops in textured yarn or hairs in cotton yarn. In addition, the tension applied to the yarn under test is unknown. Accordingly, the yarn measurements from cone to cone are dependent on the external yarn-moving machinery of the yarn producing device, and thus subject to inconsistencies. Also, the yarn is not carefully guided or flattened while it is being imaged, leading to additional measurement inconsistency and error.